Users authorized to change the way the system behaves are often called operators. Users who rely on a system, but do not operate it, are sometimes called the audience or end user.

For example, when a driver (car operator) uses the horn to warn a pedestrian, then the driver is the horn operator and the pedestrian is the audience.[1] Another example of various types of users are the operators of electronic boards, such as in airports or in e-commerce, who update messages, contrasted with the audience who read the messages.

Unlike consumer products, the customers of systems are not the same as the users. Typically, the customer is often an organization, and the user is an employee of that organization. This implies, for example, that in case of significant loss due to use error, the customer seeks to nominate the user as accountable for the loss.[citation needed]